Method and apparatus for bi-directional data services and live television programming to mobile platforms

ABSTRACT

A system for bi-directional data content transfer between a plurality of mobile platforms, such as aircraft or cruise ships, and a ground-based control segment. The system includes the ground-based control segment, a space segment and a mobile system disposed on each mobile platform. The ground-based control segment includes an antenna which is used to transmit encoded RF signals representative of data content to the space segment. The space segment includes a plurality of satellite transponders, with one of the transponders being designated by the ground-based control segment to transpond the encoded RF signals to the mobile system. The mobile system includes steerable receive and transmit antennas. The receive antenna receives the encoded RF signals from the satellite transponder, which are thereafter decoded by a communications subsystem and transmitted to a server. The server filters off that data content not requested by any occupants on the mobile system. A local area network (LAN) receives the remaining data content and provides same to individual users on the mobile platform in accordance with previously submitted programming requests or data input by the users at access stations associated independently with each user.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation of U.S. patent applicationSer. No. 09/639,912 filed on Aug. 16, 2000, and presently pending. Thedisclosure(s) of the above application is hereby incorporated byreference.

TECHNICAL FIELD

[0002] This invention relates to worldwide systems for supplying livetelevision programming and bi-directional data services to mobileplatforms, such as aircraft, using satellite communication.

BACKGROUND OF THE INVENTION

[0003] Broadband data and video services, on which our society andeconomy have grown to depend, have heretofore generally not been readilyavailable to users on board mobile platforms such as aircraft, ships,trains, automobiles, etc. While the technology exists to deliver suchservices to all forms of mobile platforms, past solutions have beengenerally quite expensive, low data rate and/or available to only verylimited markets of government/military users and some high-end maritimemarkets (i.e., cruise ships).

[0004] At present, a wide variety of broadcast television (TV) servicesare available to terrestrial users via satellite links. Such servicesinclude commercial Direct Broadcast Satellite (DBS) services (such asDirecTV® and EchoStar®) and custom video, such as rebroadcast video,over private Fixed Satellite Services (FSS) or Broadcast SatelliteServices (BSS) satellites. The data services which can be provided viasatellite link include all conventional Internet services (e.g., email,web browsing, NetMeeting, etc.), as well as virtual private networks(VPNs) for corporate and government customers.

[0005] Previously developed systems which have attempted to provide liveTV and data services to mobile platforms have done so with only limitedsuccess. One major obstacle has been the high cost of access to suchbroadband data and video services. Another problem is the limitedcapacity of previously developed systems, which is insufficient formobile platforms carrying dozens, or even hundreds, of individuals whoeach may be simultaneously requesting different channels of programmingor different data services. Furthermore, presently existing systems aregenerally not readily scalable to address the demands of the travelingpublic.

[0006] Certain services currently available provide a limited subset ofthe above described services. One such service provides anarrow-bandwidth Internet connection to users on a mobile platform.Another service provides either TV broadcast services from availabledirect broadcast signals (i.e., EchoStar® and DirectTV®) or provides acustom TV broadcast signal through dedicated satellite links (i.e.,Airshow7). However, no system or method presently exists for providinghigh speed (i.e., greater than 64 Kbps) data networking services togroups of users on mobile or remote platforms, let alone for providingsuch high-speed networking services together with video services.

[0007] There are several operational systems that provide limitedInternet data services on commercial airlines and cruise ships. Thesesystems are very limited in their link capability (primarily usecommunication links developed for telephony) and the service is veryexpensive (greater than about $1.00 per minute for voice connection).For these reasons, and in view of adherent limitations on the capacityof such systems, such systems have met with limited commercial successand acceptance.

[0008] Current operational systems generally use Inmarsat satellitecommunication links or terrestrial wireless communication links (i.e.,the National Air Telephone System “NATS”) to achieve 2-way connectivityto mobile platforms. These connection forms have several drawbacks:

[0009] a limited connection bandwidth (typically less than 64 Kbps);

[0010] limited overall system capacity (due to limited frequencyspectrum); and high expense.

[0011] Inmarsat operates in the L-band frequency spectrum, where thereis very little bandwidth and capacity available for providing broadbandservices to the traveling public. NATS based solutions (i.e., GTE®Airfone7, AT&T® Claircom), familiar to domestic airline travelers whouse seat back-mounted telephones, also provide very limited capacitybecause of operation at L-band. These systems also suffer from theadditional problem that connectivity is only available over land.

[0012] Current mobile platform connection methods are inherently narrowband and restrict the flow of data to the point where common networkingtasks are impossible. Typically, this connectivity is achieved throughthe use of a standard computer telephone modem between the user'scomputer and the air-ground or ship-shore telephony system. In thisscenario, each user gets exclusive use of a full communications channelfor the duration of his/her networking session and effectively preventsothers from using that portion of the telephony system.

[0013] One other service that has received some attention is a servicethat provides pre-stored world-wide-web content to users on a mobileplatform. This service is anticipated to incorporate a server located ona mobile platform to provide its stored content to users on the mobileplatform through a simple touchscreen interface. The content located onthe server would be updated once every few weeks while the mobileplatform is in an inactive mode, such as when an aircraft is parked atan airport gate or a ship is docked at a port. The update of the data onthe mobile platform would be accomplished through the loading of CDROMSor swapping of hard drives on the server. Although the content stored onthe mobile platform with this service can be varied, it will never betimely.

[0014] In view of the foregoing, there is a significant need to providea system and method for providing live television programming andbi-directional data communication to users onboard mobile platforms viaone or more satellite links. More specifically, there is a need toprovide Internet data communication, Direct Broadcast Satellite Servicesvia BSS satellites, and rebroadcast video of live television programmingvia Ku or Ka-band satellites to a plurality of users onboard one or moremobile platforms, and in a manner which allows each user to request andreceive Internet or other forms of real time data, as well specific liveprogramming which he/she desires to view.

[0015] There is also a need to provide a system and method for enablinghundreds or more mobile platforms, such as aircraft, to communicate witha plurality of satellites, where each satellite includes a plurality ofindependent transponders, such that each mobile platform can communicatewith an assigned transponder to permit bi-directional datacommunications by each passenger and viewing by each passenger ofselected live TV programming.

SUMMARY OF THE INVENTION

[0016] The present invention is directed by a method and apparatus forproviding television and data services to mobile platforms, inaccordance with preferred embodiments of the present invention. In onepreferred embodiment, the system of the present invention makes use of aground based segment for receiving video and data content andtransmitting the content using radio frequency signals in accordancetherewith via a ground based antenna to a space segment. The spacesegment includes a satellite incorporating at least one transponder, andmore preferably a plurality of independent transponders, which receivesthe radio frequency (RF) signals transmitted from the antenna of theground segment and relays these signals to at least one mobile system,and more typically to a large plurality of mobile systems, using thesatellite-based transponders. Each mobile system is located on a mobileplatform (e.g., aircraft, ship, etc.) and receives the RF signals fromat least one of the satellite transponders and distributes thetransponded video and data content to individual users in accordancewith selections made by the users. Thus, each user only receives thevideo programming and/or data content that he/she specifically selectedor requested.

[0017] Optionally, but preferably, the ground-based segment includes atleast one dedicated link to an Internet service provider. One or morededicated links may also be provided to various private/corporateIntranet accounts. A content management center in the ground segment isalso in communication with a network operations center thereof forcontrolling transmission of the live television programming and otherdata to the space segment.

[0018] All information sent from the ground station to the mobileplatform is broadcast over the entire coverage region of the satellitetransponder. Each satellite is located in a geostationary orbit (GSO) orin a non-geostationary (NGSO) orbit. Packet multiplexing is preferablyused to provide multiple simultaneous access to a plurality of users oneach mobile platform.

[0019] The mobile system incorporates a suitable antenna system foreffecting bi-directional communications with its assigned transponder.In one preferred form, the antenna system comprises a steerable antennacarried by the mobile platform for receiving and transmitting RF signalsto and from the satellites within the coverage region. The antennasystem is coupled to a receiver which decodes and de-modulates thereceived RF signals to produce digital video and audio, as well as datacontent signals. These signals are preferably provided in the form ofpackets, and fed to a router which filters the packets such that onlycontent selected/requested by users on the mobile platform isdistributed to the users. In this context users are defined aspassengers, cabin crew, cockpit crew, maintenance crew, and non-humanentities such as unattended data devices. A distribution system routesthe data content directly to the proper users at access stationsassociated independently with each user, or to designated components(such as overhead monitors) located throughout the mobile platform.Thus, each user or occupant receives only the specific data content(i.e., either data or TV programming) that he/she has requested, or thedata content can simply be provided to all passengers on the mobileplatform.

[0020] The method and apparatus of the present invention thus providesthe ability to conduct bi-directional data communications between aplurality of independent mobile platforms, where each user on eachmobile platform is able to independently request and obtain Internetdata or other forms of data in real time. The present invention furtherenables the users to independently request and view selected channels oflive TV programming.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The various advantages of the present invention will becomeapparent to one skilled in the art by reading the followingspecification and subjoined claims and by referencing the followingdrawings in which:

[0022]FIG. 1 is a simplified block diagram drawing illustrating thethree major components of the system of the present invention; and

[0023]FIG. 2 is a block diagram of the mobile system carried on eachmobile platform.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Referring to FIG. 1, there is shown a system 10 in accordancewith a preferred embodiment of the present invention for providing datacontent to and from a plurality of mobile platforms 12 a-12 f in one ormore distinct coverage regions 14 a and 14 b. The system 10 generallycomprises a ground segment 16, a plurality of satellites 18 a-18 fforming a space segment 17, and a mobile system 20 disposed on eachmoving platform 12. The mobile platforms 12 could comprise aircraft,cruise ships or any other moving vehicle. Thus, the illustration of themobile platforms 12 as aircraft in the figures herein, and the referenceto the mobile platforms as aircraft throughout the following descriptionshould not be construed as limiting the applicability of the system 10to only aircraft.

[0025] The space segment 17 may include any number of satellites 18 ineach coverage region 14 a and 14 b needed to provide coverage for eachregion. Satellites 18 a, 18 b, 18 d and 18 e are preferably Ku orKa-band satellites. Satellites 18 c and 18 f are Broadcast SatelliteServices (BSS) satellites. Each of the satellites 18 are further locatedin a geostationary orbit (GSO) or a non-geostationary orbit (NGSO).Examples of possible NGSO orbits that could be used with this inventioninclude low Earth orbit (LEO), medium Earth orbit (MEO) and highlyelliptical orbit (HEO). Each of the satellites 18 includes at least oneradio frequency (RF) transponder, and more preferably a plurality of RFtransponders. For example satellite 18 a is illustrated having fourtransponders 18 a ₁-18 a ₄. It will be appreciated that each othersatellite 18 illustrated could have a greater or lesser plurality of RFtransponders as required to handle the anticipated number of mobileplatforms 12 operating in the coverage area. The transponders provide“bent-pipe” communications between the aircraft 12 and the groundsegment 16. The frequency bands used for these communication links couldcomprise any radio frequency band from approximately 10 MHz to 100 GHz.The transponders preferably comprise Kuband transponders in thefrequency band designated by the Federal Communications Commission (FCC)and the International Telecommunications Union (ITU) for fixed satelliteservices FSS or BSS satellites. Also, different types of transpondersmay be employed (i.e., each satellite 18 need not include a plurality ofidentical types of transponders) and each transponder may operate at adifferent frequency. Each of the transponders 18 a ₁-18 a ₄ furtherinclude wide geographic coverage, high effective isotropic radiatedpower (EIRP) and high gain/noise temperature (G/T).

[0026] With further reference to FIG. 1, the ground segment 16 includesa ground station 22 in bi-directional communication with a contentcenter 24 and a network operations center (NOC) 26. A second groundstation 22 a located in the second coverage area 14 b may be used ifmore than one distinct coverage area is required for the service. Inthis instance, ground station 22 a would also be in bi-directionalcommunication with the NOC 26 via a terrestrial ground link or any othersuitable means for establishing a communication link with the NOC 26.The ground station 22 a would also be in bi-directional communicationwith a content center 24 a. For the purpose of discussion, the system 10will be described with respect to the operations occurring in coverageregion 14 a. However, it will be understood that identical operationsrelative to the satellites 18 d-18 f occur in coverage region 14 b. Itwill also be understood that the invention may be scaled to any numberof coverage regions 14 in the manner just described.

[0027] The ground station 22 comprises an antenna and associated antennacontrol electronics needed for transmitting data content to thesatellites 18 a and 18 b. The antenna of the ground station 22 may alsobe used to receive data content transponded by the transponders 18 a₁-18 a ₄ originating from each mobile system 20 of each aircraft 12within the coverage region 14 a. The ground station 22 may be locatedanywhere within the coverage region 14 a. Similarly, ground station 22a, if incorporated, can be located anywhere within the second coveragearea 14 b.

[0028] The content center 24 is in communication with a variety ofexternal data content providers and controls the transmission of videoand data information received by it to the ground station 22.Preferably, the content center 24 is in contact with an Internet serviceprovider (ISP) 30, a video content source 32 and a public switchedtelephone network (PSTN) 34. Optionally, the content center 24 can alsocommunicate with one or more virtual private networks (VPNs) 36. The ISP30 provides Internet access to each of the occupants of each aircraft12. The video content source 32 provides live television programming,for example, Cable News Network® (CNN) and ESPN®. The NOC 26 performstraditional network management, user authentication, accounting,customer service and billing tasks. The content center 24 a associatedwith the ground station 22 a in the second coverage region 14 b wouldalso preferably be in communication with an ISP 38, a video contentprovider 40, a PSTN 42, and optionally a VPN 44. An optional airtelephone system 28 may also be included as an alternative to thesatellite return link.

[0029] Referring now to FIG. 2, the mobile system 20 disposed on eachaircraft 12 will be described in greater detail. Each mobile system 20includes a data content management system in the form of a router/server50 (hereinafter “server”) which is in communication with acommunications subsystem 52, a control unit and display system 54, and adistribution system in the form of a local area network (LAN) 56.Optionally, the server 50 can also be configured for operation inconnection with a National Air Telephone System (NATS) 58, a crewinformation services system 60 and/or an in-flight entertainment system(IFE) 62.

[0030] The communications subsystem 52 includes a transmitter subsystem64 and a receiver subsystem 66. The transmitter subsystem 64 includes anencoder 68, a modulator 70 and an Up-converter 72 for encoding,modulating and up-converting data content signals from the server 50 toa transmit antenna 74. The receiver subsystem 66 includes a decoder 76,a demodulator 78 and a down-converter 80 for decoding, demodulating anddown-converting signals received by the receive antenna 82 into basebandvideo and audio signals, as well as data signals. While only onereceiver subsystem 66 is shown, it will be appreciated that preferably aplurality of receiver subsystems 66 will typically be included to enablesimultaneous reception of RF signals from a plurality of RFtransponders. If a plurality of receiver subsystems 66 are shown, then acorresponding plurality of components 76-80 will also be required.

[0031] The signals received by the receiver subsystem 66 are then inputto the server 50. A system controller 84 is used to control allsubsystems of the mobile system 20. The system controller 84, inparticular, provides signals to an antenna controller 86 which is usedto electronically steer the receive antenna 82 to maintain the receiveantenna pointed at a particular one of the satellites 18, which willhereinafter be referred to as the “target” satellite. The transmitantenna 74 is slaved to the receive antenna 82 such that it also tracksthe target satellite 18. It will be appreciated that some types ofmobile antennas may transmit and receive from the same aperture. In thiscase the transmit antenna 74 and the receive antenna 82 are combinedinto a single antenna.

[0032] With further reference to FIG. 2, the local area network (LAN) 56is used to interface the server 50 to a plurality of access stations 88associated with each seat location on board the aircraft 12 a. Eachaccess station 88 can be used to interface the server 50 directly with auser's laptop computer, personal digital assistant (PDA) or otherpersonal computing device of the user. The access stations 88 could alsoeach comprise a seat back mounted computer/display. The LAN 56 enablesbi-directional communication of data between the user's computing deviceand the server 50 such that each user is able to request a desiredchannel of television programming, access a desired website, accesshis/her email, or perform a wide variety of other tasks independently ofthe other users on board the aircraft 12.

[0033] The receive and transmit antennas 82 and 74, respectively, maycomprise any form of steerable antenna. In one preferred form, theseantennas comprise electronically scanned, phased array antennas. Phasedarray antennas are especially well suited for aviation applicationswhere aerodynamic drag is important considerations. One particular formof electronically scanned, phased array antenna suitable for use withthe present invention is disclosed in U.S. Pat. No. 5,886,671, assignedto The Boeing Co.

[0034] Referring further to FIG. 1, in operation of the system 10, thedata content is preferably formatted into Internet protocol (IP) packetsbefore being transmitted by either the ground station 22, or from thetransmit antenna 74 of each mobile system 20. For the purpose ofdiscussion, a transmission of data content in the form of IP packetsfrom the ground station 22 will be referred to as a “forward link”transmission. IP packet multiplexing is also preferably employed suchthat data content can be provided simultaneously to each of the aircraft12 operating within the coverage region 14 a using unicast, multicastand broadcast transmissions.

[0035] The IP data content packets received by each of the transponders18 a ₁-18 a ₄ are then transponded by the transponders to each aircraft12 operating within the coverage region 14 a. While multiple satellites18 are illustrated over coverage region 14 a, it will be appreciatedthat at the present time, a single satellite is capable of providingcoverage to an area encompassing the entire continental United States.Thus, depending upon the geographic size of the coverage region and themobile platform traffic anticipated within the region, it is possiblethat only a single satellite incorporating a single transponder may beneeded to provide coverage for the entire region. Other distinctcoverage regions besides the continental United States include Europe,South/Central America, East Asia, Middle East, North Atlantic, etc. Itis anticipated that in service regions larger than the continentalUnited States, that a plurality of satellites 18 each incorporating oneor more transponders may be required to provide complete coverage of theregion.

[0036] The receive antenna 82 and transmit antenna 74 are eachpreferably disposed on the top of the fuselage of their associatedaircraft 18. The receive antenna 74 of each aircraft receives the entireRF transmission of encoded RF signals representing the IP data contentpackets from at least one of the transponders 18 a ₁-18 a ₄. The receiveantenna 82 receives horizontally polarized (HP) and vertically polarized(VP) signals which are input to at least one of the receivers 66. Ifmore than one receiver 66 is incorporated, then one will be designatedfor use with a particular transponder 18 a ₁-18 a ₄ carried by thetarget satellite 18 to which it is pointed. The receiver 66 decodes,demodulates and down-converts the encoded RF signals to produce videoand audio signals, as well as data signals, that are input to the server50. The server 50 operates to filter off and discard any data contentnot intended for users on the aircraft 12 a and then forwards theremaining data content via the LAN 56 to the appropriate access stations88. In this manner, each user receives only that portion of theprogramming or other information previously requested by the user.Accordingly, each user is free to request and receive desired channelsof programming, access email, access the Internet and perform other datatransfer operations independently of all other users on the aircraft 12a.

[0037] An advantage of the present invention is that the system 10 isalso capable of receiving DBS transmissions of live televisionprogramming (e.g., news, sports, weather, entertainment, etc.). Examplesof DBS service providers include DirecTV® and Echostar®. DBStransmissions occur in a frequency band designated for broadcastsatellite services (BSS) and are typically circularly polarized in NorthAmerica. Therefore, a linear polarization converter may be optionallyadded to receive antenna 82 for receiving broadcast satellite servicesin North America. The FSS frequency band that carries the data servicesand the BSS frequency band that carries DBS transmissions are adjacentto each other in the Ku-band. In one optional embodiment of the system10, a single Ku-band receive antenna can be used to receive either DBStransmissions from DBS satellites 18 c and 18 f in the BSS band or dataservices in the FSS band from one of the FSS satellites 18 a or 18 b, orboth simultaneously using the same receive antenna 82. Simultaneousreception from multiple satellites 18 is accomplished using a multi-beamreceive antenna 82 or by using a single beam receive antenna 82 withsatellites co-located in the same geostationary orbit slot.

[0038] Rebroadcast television or customized video services are receivedand processed by the mobile system 20 in exactly the same way.Rebroadcast or customized video content is obtained from the videocontent source 32 and transmitted via the ground station 22 to the FSSsatellites 18 a and 18 b. The video content is appropriately encoded fortransmission by the content center 24 before being broadcast by theground station 22. Some customization of the rebroadcast content mayoccur on the server 50 (FIG. 2) of the mobile system 20 to tailoradvertisements and other information content to a particular market orinterest of the users on the aircraft 12 a.

[0039] The bulk of data content provided to the users on each aircraft12 is provided by using a private portal data content. This isimplemented as a set of HTML pages housed on the server 50 of eachmobile system 20. The content is kept fresh by periodically sendingupdated portions from a ground-based server located in content center24, and in accordance with a scheduling function controlled by the NOC26 of the ground segment 16. The server 50 can readily be configured toaccept user log-on information to support authentication andauthorization of users and to keep track of user and network accountinginformation to support a billing system. The authorization andaccounting systems can be configured to communicate with the groundsegment 16 to transfer accumulated data at convenient intervals to theNOC 26.

[0040] The system 10 of the present invention also provides directInternet connectivity via satellite links for a variety of purposes,such as when a user on board the aircraft 12 desires to obtain datacontent that is not cached on server 50, or as an avenue for contentsources to provide fresh content for the private portals. The server 50may be used to cache the most frequently requested web pages as well asto host a domain name system (DMS) look-up table of the most frequentlyaccessed domains. The DMS look-up table is preferably maintained by thecontent center 24 and is periodically updated on the mobile system 20.Refreshing of the cached content of the portal may be accomplished byin-flight, periodic “pushed” cache refresh or at the gate of an airportterminal using any form of wired or wireless connection to the aircraft12 a, or via a manual cache refresh by a crew member of the aircraft 12a carrying on board a CD ROM and inserting it into the cache server. Theinvention 10 implements the in-flight periodic, pushed cache refreshupdates over the satellite links. Preferably, refreshing of the cachecontent occurs during periods of low demand on the satellite links.

[0041] The optional air telephone system 28 can also be employed withthe system 10 when line-of-sight links to the ground segments 16 areestablished to provide the physical infrastructure. For example, anoptional implementation incorporating an air telephone systems can beused for low data rate return links (2.4 kbps to 9.6 kbps). It will berecognized that other regions, such as Europe and Asia, have similar airtelephone systems that communicate with aircraft using terrestrialcellular communications links. Air telephone systems (e.g., NATS inNorth America) were designed for carrying telephony traffic, but havebeen adapted to pass single user per call, point to point analog modemdata. With the present invention, the aggregate return link traffic fromthe mobile system 20 is combined in server/router 50, a switch or a PBX(not shown) and then coupled into the air telephone return link via ananalog modem or directly via a digital interface (e.g., CEPT-E1).Expanded capacity can be provided by establishing multiple simultaneousconnections from the router/switch into the air telephone system.Multi-link, point to point (PPP) data encapsulation can be used toaccomplish the splitting/recombining of the data streams between theairborne and NOC 26 routers. In addition to expanded capacity, thetolerance to a single connection failure is increased with multipleconnections through the air telephone system. The hand-over betweenseparate air telephone system antenna towers is managed by the airtelephone system and the connection between the respective air andground routers is automatically maintained as the mobile platformtraverses multiple coverage areas.

[0042] A significant anticipated application of the present invention isin connection with aircraft that fly extended periods of time over waterand remote regions (including polar regions) of the Earth where there islittle or no current satellite transponder coverage. The presentinvention can operate with GSO satellites launched in the future intoorbit over oceans, or a new constellation of NGSO satellites to providefull Earth coverage (including the poles).

[0043] Referring further to FIG. 1, a transmission of data content fromthe aircraft 12 a to the ground station 22 will be described. Thistransmission is termed a “return link” transmission. The antennacontroller 86 causes the transmit antenna 74 to maintain the antennabeam thereof pointed at the target satellite 18 a. The channels used forcommunication from each mobile system 20 back to the ground station 22represent point-to-point links that are individually assigned anddynamically managed by the NOC 26 of the ground segment 16. For thesystem 10 to accommodate several hundred or more aircraft 12, multipleaircraft will need to be assigned to each transponder carried by a givensatellite 18. The preferred multiple access methods for the return linkare code division multiple access (CDMA), frequency divisional multipleaccess (FDMA), time division multiple access (TDMA) or combinationsthereof. Thus, multiple mobile systems 20 may be assigned to a singletransponder 18 a ₁-18 a ₄. Where a greater number of aircraft 12incorporating a mobile system 20 are operated within the coverage region14 a, then the number of transponders required increases accordingly.

[0044] The receive antenna 82 may implement a closed-loop trackingsystem for pointing the antenna beam and for adjusting the polarizationof the antennas based on receive signal amplitude. The transmit antenna74 is slaved to the point direction and polarization of the receiveantenna 82. An alternative implementation could use an open-looptracking method with the pointing direction and polarization determinedby knowledge of mobile platform position and attitude using an on-boardinertial reference unit (IRU) and knowledge of the location of thesatellites 18.

[0045] Encoded RF signals are transmitted from the transmit antenna 74of the mobile system 20 of a given aircraft 12 to an assigned one of thetransponders 18 a ₁-18 a ₄, and transponded by the designatedtransponder to the ground station 22. The ground station 22 communicateswith the content center 24 to determine and provide the appropriate databeing requested by the user (e.g., content from the world wide web,email or information from the user's VPN).

[0046] An additional concern that must be taken into account with thesystem 10 is the potential for interference that may result from thesmall aperture size of the receive antenna 82. The aperture size of thereceive antenna 82 is typically smaller than conventional “very smallaperture terminal” (VSAT) antennas. Accordingly, the beam from thereceive antenna 82 may encompass adjacent satellites along thegeosynchronous arc. This can result in interference from satellitesother than the target satellite being received by a particular mobilesystem 20. To overcome this potential problem, the system 10 preferablyuses a lower than normal forward link data rate that overcomes theinterference from adjacent satellites. For example, the system 10operates at a preferred forward link data rate of at least about 5 Mbpsper transponder, using a typical FSS Ku-band transponder (e.g.,Telstar-6) and an antenna having an active aperture of about 17 inchesby 24 inches (43.18 cm by 60.96 cm). For comparison purposes, a typicalKu-band transponder usually operates at a data rate of approximately 30Mbps using conventional VSAT antennas.

[0047] Using a standard digital video broadcast (DVB) waveform, theforward link signal typically occupies less than 8 MHz out of a totaltransponder width of 27 MHz. However, concentrating the transponderpower in less than the full transponder bandwidth could create aregulatory concern. FCC regulations presently regulate the maximumeffective isotropic radiated power (EIRP) spectral density from atransponder to prevent interference between closely spaced satellites.Accordingly, in one preferred embodiment of the present invention,spread spectrum modulation techniques are employed in modulator 70 to“spread” the forward link signal over the transponder bandwidth usingwell known signal spreading techniques. This reduces the spectraldensity of the transponded signal, thus eliminating the possibility ofinterference between two or more mobile systems 20.

[0048] It is also equally important that the transmit antenna 74 meetsregulatory requirements that prevent interference to satellites adjacentto the target satellite 18. The transmit antennas used in most mobileapplications also tend to be smaller than conventional VSAT antennas(typically reflector antennas that are 1 meter in diameter). Mobiletransmit antennas used for aeronautical applications should have lowaerodynamic drag, be lightweight, have low power consumption and be ofrelatively small size. For all these reasons, the antenna aperture ofthe transmit antenna 74 is preferably smaller than a conventional VSATantenna. VSAT antennas are sized to create an antenna beam that isnarrow enough to illuminate a single FSS satellite along thegeosynchronous arc. This is important because FSS satellites are spacedat 2° intervals along the geosynchronous arc. The smaller than normalantenna aperture of the transmit antenna 74 used with the presentinvention, in some instances, may create an antenna beam that is wideenough to irradiate satellites that are adjacent to the target satellitealong the geosynchronous arc, which could create an interferenceproblem. This potential problem is eliminated by employing spreadspectrum modulation techniques on the return link transmissions as well.The transmitted signal from the transmit antenna 74 is spread infrequency to produce an interfering signal at the adjacent satellitethat is below the threshold EIRP spectral density at which the signalwould interfere. It will be appreciated, however, that spread spectrummodulation techniques may not be required if the angular spacing betweensatellites within a given coverage region is such that interference willnot be a problem.

[0049] It will be appreciated that the system 10 of the presentinvention provides a means for providing bi-directional data contenttransfer to a large plurality of independent users on-board a largenumber of mobile platforms. The system 10 further enables data contentsuch as rebroadcast video services, broadcast video services and otherforms of data content to be provided in real time to a large pluralityof mobile platforms such as aircraft, ships or virtually any other formof mobile platform carrying individuals who desire to accessground-based data content sources or to view live television andprogramming. The system further allows multiple mobile platforms withina given coverage region to communicate with one or a plurality oftransponders within the given coverage region and to transmit datacontent via a satellite back to a ground-based control system.Accordingly, individual users on-board the mobile platform are able toindependently access and obtain various forms of data content as well asselected channels of live television programming. Importantly, thesystem 10 of the present invention is scalable to accommodate large orsmall pluralities of mobile platforms, and also scalable over manysatellites and coverage regions.

[0050] Those skilled in the art can now appreciate from the foregoingdescription that the broad teachings of the present invention can beimplemented in a variety of forms. Therefore, while this invention hasbeen described in connection with particular examples thereof, the truescope of the invention should not be so limited since othermodifications will become apparent to the skilled practitioner upon astudy of the drawings, specification and following claims.

What is claimed is:
 1. A system for providing data content to aplurality of mobile platforms via at least one satellite having at leastone radio frequency (RF) transponder, and for transmitting data contentfrom said mobile platforms via said RF transponder to a ground-basedcontrol center, comprising: an independent mobile system associated witheach said mobile platform and carried by each said mobile platform; aground-based antenna system associated with said ground-based controlcenter for transmitting encoded RF signals representative of said datacontent via said RF transponder to said mobile system; each said mobilesystem comprising: a steerable transmit antenna and a steerable receiveantenna; a communications subsystem in communication with each of saidantennas for generating baseband video signals and data signals fromsaid encoded RF signals received by said receive antenna, and forproducing encoded signals from data transmissions input by each of aplurality of occupants; a data content management system for filteringof portions of said data content not addressed to occupants on saidmobile platform; a network for distributing said baseband video signalsand said data signals output from said data content management system tosaid occupants, said network including a plurality of access stationswhereby individual occupants receive only specific subportions of saidbaseband video signals and said data signals relating to previousinformation selections made by said occupants; and said independentmobile system also operating to transmit said signals input by each ofsaid occupants from each of said access stations, via said RFtransponder, to said ground-based antenna system.
 2. The system of claim1, wherein said access stations are adapted to be coupled to personalcomputing devices operated by each of said occupants.
 3. The system ofclaim 1, wherein said data content management system comprises a fileserver.
 4. The system of claim 1, wherein said satellite comprises aplurality of RF transponders, and wherein said ground based controlcenter designates one of said transponders to communicate in dedicatedfashion with a designated one of said mobile platforms.
 5. The system ofclaim 1, wherein said network comprises a local area network.
 6. Asystem for providing real time video signals to a mobile receivingplatform via a satellite having at least one radio frequency (RF)transponder, the system comprising: a ground based system fortransmitting RF signals representative of said video signals to saidsatellite; a mobile receiving system disposed on said mobile receivingplatform comprising: an antenna for receiving said RF signals from saidRF transponder; an antenna control system for use in steering saidantenna to track said satellite as said mobile receiving platform is inmotion; a communications system responsive to signals received by saidantenna for generating baseband video signals in accordance therewith; adata content management system responsive to said communications systemfor determining which portions of said baseband video signals are to betransmitted to each of a plurality of access stations on said mobilereceiving platform for viewing by individuals on said mobile receivingplatform; and a distribution system for routing said portions of saidbaseband video signals to specific ones of said access stations inresponse to requests by said occupants, such that each said occupantreceives only a portion of said baseband video signals in accordancewith said request made by each said occupant.
 7. The system of claim 6,wherein said communications system comprises a plurality of integratedreceiver/decoders for decoding, demodulating and digital-to-analogconverting received RF signals into said baseband video signals.
 8. Thesystem of claim 6, wherein said data content management system comprisesa server.
 9. The system of claim 6, wherein said baseband video signalsrepresent live television signals.
 10. The system of claim 6, whereinsaid baseband video signals represent direct broadcast televisionsignals.
 11. The system of claim 6, wherein said ground based systemcomprises a network operations center for managing accounting andbilling operations associated with access to the system by each user.12. The system of claim 6, wherein said ground segment operates totransmit encoded data signals to said transponder of said satellite; andwherein said communications system operates to de-modulate and D/Aconvert said RF signals to produce said baseband data signals.
 13. Asystem for supplying a plurality of channels of data content to aplurality of independent mobile receiving platforms, wherein each saidmobile receiving platform has a plurality of occupants, and forreceiving data content transmitted from said mobile receiving platformby said occupants, said system comprising: a ground based antenna fortransmitting encoded radio frequency (RF) signals representing said datacontent; at least one satellite having a plurality of RF transponders inorbit over a desired geographical coverage area within which said mobileplatforms are traveling, for transponding said encoded RF signals; amobile receiving system disposed on each said mobile receiving platform,each said mobile system comprising: an antenna system including areceive antenna for receiving said encoded RF signals from a designatedone of said RF transponders, and a transmit antenna for transmittingsaid data content to a designated one of said RF transponders; anantenna control system for steering said transmit and receive antennasto track said satellite as said mobile receiving platform is in motion;a communications system responsive to said encoded RF signals receivedby said receive antenna for demodulating and decoding said encoded RFsignals to produce baseband video signals and data signals; saidcommunications system including a system for transmitting data contentfrom each of said occupants, via said transmit antenna, to saiddesignated one of said transponders; a data content management systemresponsive to said communications system for determining which portionsof said baseband video signals and which portions of said data signalsare to be transmitted to specific ones of a plurality of access stationson said mobile receiving platform for use by said occupants of saidmobile receiving platform; and a network system for routing saidportions of said baseband video signals and said data signals tospecific ones of said access stations in response to requests by saidoccupants, such that each said occupant receives only a requestedportion of said baseband video signals or a requested portion of saiddata signals.
 14. The system of claim 13, wherein said communicationssystem comprises a plurality of integrated receiver/decoders.
 15. Thesystem of claim 13, wherein said data content management systemcomprises a server.
 16. The system of claim 13, further comprising adata system for supplying crew information services to said data contentmanagement system.
 17. The system of claim 13, further comprising an airtelephone system on board said mobile platform for transmitting dataservices to at least one ground based voice telephony receiving stationwithin said coverage area.
 18. A system for enabling individualoccupants on board a moving platform to transmit and receive datacontent in real time from a ground based data source, said systemcomprising: a ground based system for transmitting radio frequency (RF)signals representative of said data content obtained from a data contentsource; a satellite system having at least one RF transponder fortransponding RF signals received from said ground based system to saidmobile platform, and transponding RF signals received from said movingplatform to said ground based system; a mobile communications systemdisposed on said mobile platform including: a receive antenna forreceiving RF signals from said RF transponder; a transmit antenna fortransmitting RF signals to said RF transponder; a communicationssubsystem in communication with said receive antenna and said transmitantenna for converting said received RF signals into data content, andfor converting user data transmitted by said occupants into RF signalsto be transmitted by said transmit antenna to said RF transponder; and adata content management system for receiving said data content from saidcommunications subsystem and determining which subportions of said datacontent is to be distributed to specific ones of said occupants; and adistribution system for distributing said subportions of said datacontent to said occupants such that each said occupant receives onlyspecific ones of said subportions of said data content in accordancewith previous information transmissions made by each said occupant. 19.The system of claim 18, wherein said distribution system comprises alocal area network (LAN).
 20. The system of claim 18, wherein saiddistribution system further comprises a plurality of independent accessstations capable of interfacing with an electronic device of an occupantof said mobile platform.
 21. A system for facilitating bi-directionalcommunication between a ground-based control center and a plurality ofmobile platforms, of data content via a satellite having a plurality of(RF) transponders, said system comprising: a ground based antenna fortransmitting encoded RF signals from said ground-based control centerrepresenting said data content; a mobile receiving system disposed oneach said mobile platform, each said mobile receiving system comprising:a steerable receive antenna for receiving said encoded RF signals from adesignated one of said RF transponders of said satellite; an antennacontrol system for steering said receive and transmit antennas to tracksaid satellite as said mobile receiving platform is in motion; acommunications system responsive to said encoded RF signals received bysaid receive antenna for generating output signals representative oflive television programming and Internet data; a server responsive tosaid communications system for filtering off portions of said livetelevision programming and portions of said Internet data representingdata content which have not been requested by any of said occupants ofits associated said mobile platform, and filtering off portions of saiddata content not directed to any occupant of said mobile platform; and anetwork system for routing said portions of said output signals and saidportions of said Internet data to specific ones of a plurality of accessstations in accordance with inputs made at said access stations by eachof said occupants.
 22. The system of claim 21, wherein said steerablereceive antenna comprises an electronically steerable, phased arrayantenna.
 23. A method of transmitting data content between a mobilereceiving platform and a ground-based control segment, comprising thesteps of: using a ground-based antenna associated with said ground-basedcontrol segment to transmit encoded radio frequency (RF) signalscorresponding to said data content; using a satellite having a pluralityof transponders to receive said encoded RF signals and to transpond saidencoded RF signals, via one of said transponders designated by saidground-based control segment, to said mobile receiving platform; using asteerable antenna carried by said mobile receiving platform to receivesaid encoded RF signals; causing said steerable antenna to track saidsatellite as said mobile receiving platform is in motion to therebymaintain constant radio frequency contact with said satellite; decodingand demodulating said encoded RF signals to produce a plurality of datasignals representative of said data content; filtering off said datasignals that have not been requested by any occupant of said mobileplatform to produce a limited subset of data content; distributingselected portions of said subset of data content to access stationsassociated with said occupants in accordance with requests of each saidoccupant such that each said occupant receives only selected portions ofsaid subset of data content corresponding to his/her previouslysubmitted requests; and transmitting encoded RF signals representativeof information requests from said users to said satellite.